import java.util.Random;

public class random {
    //定义方法随机产生一个1到5的验证码
    //验证码格式
    //长度为五
    //前四位是大写字母或者小写字母
    //最后一位是数字
    public static void main(String[] args) {
        Random r = new Random();
        char chs[] = new char[56];
        for (int i = 0; i < chs.length; i++) {
            if (i <= 25) {
                chs[i] = (char) (97 + i);
            } else {
                chs[i] = (char) (65 + i - 26);
            }
        }

        String result = "";
        for (int i = 0; i < 4; i++) {
            int number = r.nextInt(chs.length);
            result = result + chs[number];
        }
        int number = r.nextInt(10);
        result = result + number;
        System.out.println(result);
    }
}





